水杨酸与蔬菜作物抗性关系的研究进展

水杨酸在植物的抗病性方面发挥着重要的作用,近年来的研究表明,水杨酸在植物抗冷、热、盐、干旱、臭氧、重金属等环境胁迫方面有明显的作用。对近年来有关水杨酸在蔬菜抗逆境胁迫方面的研究进展进行综述,并提出一些研究思路。     

Pollen grains of heat tolerant tomato cultivars retain higher carbohydrate concentration under heat stress conditions

Exposure to high temperatures (heat stress) causes reduced yield in tomatoes (Lycopersicon esculentum), mainly by affecting male gametophyte development. Two experiments were conducted where several tomato cultivars were grown under heat stress, in growth chambers (day/night temperatures of 31/25 °C) or in greenhouses (day/night temperatures of 32/26 °C), or under control (day/night temperatures of 28/22 °C) conditions. In heat-sensitive cultivars, heat stress caused a reduction in the number of pollen grains, impaired their viability and germinability, caused reduced fruit set and markedly reduced the numbers of seeds per fruit. In the heat-tolerant cultivars, however, the number and quality of pollen grains, the number of fruits and the number of seeds per fruit were less affected by high temperatures. In all the heat-sensitive cultivars, the heat-stress conditions caused a marked reduction in starch concentration in the developing pollen grains at 3 days before anthesis, and a parallel decrease in the total soluble sugar concentration in the mature pollen, whereas in the four heat-tolerant cultivars tested, starch accumulation at 3 days before anthesis and soluble sugar concentration at anthesis were not affected by heat stress. These results indicate that the carbohydrate content of developing and mature tomato pollen grains may be an important factor in determining pollen quality, and suggest that heat-tolerant cultivars have a mechanism for maintaining the appropriate carbohydrate content under heat stress.     

Drought responses of six ornamental herbaceous perennials

Although low water use landscaping is becoming common in arid regions, little is known about drought tolerance and drought responses of many ornamental plants, especially herbaceous perennials. Drought responses were assessed for six herbaceous ornamental landscape perennials in a 38 l pot-in-pot system in northern Utah over a 2-year period. The first year was an establishment period. During the second year, drought responses were evaluated for established Echinacea purpurea (L.) Moench, Gaillardia aristata Pursh, Lavandula angustifolia P. Mill., Leucanthemum × superbum (J.W. Ingram) Berg. ex Kent, ‘Alaska’, Penstemon barbatus Roth var. praecox nanus rondo, and Penstemon × mexicali Mitch. ‘Red Rocks’. Plants were irrigated at frequencies of 1 (control), 2, or 4 weeks between June and September, simulating well-watered conditions, moderate drought, or severe drought. Osmotic potential (Ψ_s), gas exchange, visual quality, leaf area, and dry weight were assessed. In a confined root zone, P. barbatus showed the greatest tolerance to all levels of drought, avoiding desiccation by increasing root:shoot ratio and decreasing stomatal conductance as water became limiting. L. angustifolia and P. × mexicali showed tolerance to moderate drought conditions, but died after exposure to the first episode of severe drought. Neither G. aristata nor L. superbum were able to regulate shoot water loss effectively. Instead, both species displayed drought avoidance mechanisms, dying back when water was limiting and showing new growth after they were watered. Compared to control plants, G. aristata shoot dry weight was reduced by 50% and 84%, and L. superbum shoot dry weight was reduced by 47% and 99% for the 2- and 4-week irrigation intervals, respectively. Root dry weights were affected similarly for both species. E. purpurea exhibited poor visual quality at all irrigation intervals, in particular wilting severely in both drought treatments, but regaining turgor when watered again. P. barbatus is recommended for ornamental landscapes that receive little or no supplemental irrigation, while E. purpurea is not recommended for low water landscapes because of low visual quality under even mild drought.     

二月兰耐阴性的研究

用黑色遮阴网设置四种光强(全日照、全日照的33%、全日照的11%、全日照的3%),研究二月兰的耐阴性,结果表明:二月兰具有较典型阴生植物结构特点,其叶绿素含量随着光强降低而增加,叶绿素a/b则降低。二月兰对光照适应能力较强,全日照的3%下仍具有很高的观赏价值。但最适光照为全日照的33%。     

加工番茄种子发芽及苗期耐冷性差异研究

通过低温下种子发芽鉴定和苗期低温处理后生理生化指标的测定等方法,研究了9个加工番茄品种种子萌发期和幼苗期的耐冷反应。结果表明,供试材料对低温反应存在差异;种子萌发期耐冷性鉴定温度为15、20℃;低温下植株电解质渗透率、叶片细胞内可溶性糖含量均有上升;根据各品种种子发芽率、幼苗冷害指数、植株电解质渗透率、叶片可溶性糖含量综合评定,UC-82、里格尔、石番18号、红霸这4个品种抗冷性较好。     

内蒙古牧区传统乳制品中耐酸及耐胆盐植物乳杆菌的筛选

试验对从内蒙古通辽市科左后旗和扎鲁特旗牧民家的乳样中分离的27株植物乳杆菌的耐酸及耐胆盐特性进行研究。结果显示，有20株菌能耐受0．3％的牛胆酸钠，且对pH3．0的生长环境表现出不同程度的耐受性。其中8株菌耐受性较强，存活率最高可达150．6％，其余菌株从15．5％-39．8％不等。     

披碱草野生种质材料芽期耐盐性研究

通过对20份来自不同地区的披碱草野生种质材料在0、0.4%、0.6%、0.8%、1.0%浓度盐胁迫下的相对发芽率、相对发芽势、致死浓度等指标的综合评价,筛选出耐盐材料4份(G8、G17、G18、G19),分别来自甘肃古浪县、山西沁源、甘肃古浪县、山西五台山;敏盐材料3份(G2、G3、G5),分别来自北京百花山、北京灵山、新疆吉阜康白杨沟;其他为中等耐盐材料。     

高温胁迫下冷季型草坪草的耐热性评价

对5个典型冷季型草坪草品种在海南进行耐热性试验.在大田高温胁迫环境下,草坪草热害症状最初表现为叶片发生萎蔫,生长率减缓或停滞,但其是否受害却最先反映在叶片灼伤率上,受害最终表现为草坪盖度和根系生长量的下降.叶片灼伤率是判断草坪草早期是否受到热伤害最敏感的指标.耐热性评价结果:Pacer高羊茅Festuc atundincea cv.Pacer＞Houndog高羊茅F.arundinacea cv.Houndog＞Merit草地早熟禾Poa pratensis cv.Merit＞Derby黑麦草Lolium pernne cv.Derby＞Cobra匍匐翦股颖Agrostis palustris cv.Cobra.28～36 ℃可认为是冷季型草坪草的临界受害温度区间,28～32 ℃为初始受害温度区间,32～36 ℃为致死温度区间.     

不同耐旱性玉米根系解剖结构比较研究

以大田生长的不同耐旱性玉米品种为试验材料,采用徒手切片法和常规石蜡制片法对玉米的初生根和各层次生根的基部、中部和根毛区显微结构进行了系统研究和比较.结果显示:与不酎旱品种玉米的根系相比,耐旱玉米的初生胚根的皮层细胞层数较少,木质部导管数量较多、导管直径较小;各层次生根的皮层细胞层教相对较少,木质部导管数量相对较多,导管直径相对较小.     

Differential ability of alcohol fermentation between the seeds of flooding-tolerant and flooding-susceptible varieties of Echinochloa crus-galli (L.) Beauv.

Seed germination and respiratory metabolism under aerobic and anaerobic conditions were studied in the flooding-tolerant and flooding-susceptible varieties of Echinochloa crus-galli with an identical genome and common ancestry . In the flooding-tolerant E. crus-galli var. formosensis , the seeds imbibed under nitrogen could germinate and exhibited an I/N quotient > 0.6. They accelerated glycolysis and concomitantly produced large and equimolar quantities of carbon dioxide and ethanol, suggesting that the seeds of this variety showed operation of the Pasteur effect and respired through alcohol fermentation under anaerobic conditions. The seeds excreted most of the toxic fermentation product. In contrast, the seeds of the flooding-susceptible E. crus-galli var. praticola were capable of germinating only under aerobic conditions through the conventional aerobic respiration and were unable to anaerobically respire to germinate through alcohol fermentation regardless of the presence of both sufficient alcohol dehydrogenase activity and a high redox charge of the pyridine nucleotides.